Copy sheet drying and delivering device for reprographic machine

ABSTRACT

An improved copy sheet drying and delivering device for an electrostatic copy machine of the liquid developing type is provided in which the drying station following the liquid developing station comprises a pair of squeezing rollers and at least a pair of drying rollers constituted by a roller covered with natural or synthetic leather known on the market as &#39;&#39;&#39;&#39;chamois leather&#39;&#39;&#39;&#39; or &#39;&#39;&#39;&#39;buck skin&#39;&#39;&#39;&#39; and a pressing counter rollers; and in which the longitudinal axes of said pairs of squeezing and drying rollers are disposed in the machine along an ascendent curved path, the nip of the last pair of drying roller being disposed adjacent to the sheet output slit of the machine, this slit is disposed at such a height with respect to the copy accumulating plane of the machine as to cause the outcoming sheet to take up a curved direction, the concavity of which is turned toward the machine and such as to upset it so that the image becomes turned downward toward the accumulating surface.

United States Patent Ravera et al.

[ 51 Aug. 12, 1975 [75] Inventors: Giovanni Ravera; Giorgio Siletto,

both of Turin, Italy [73] Assignee: Ing. C. Olivetti & C., S.p.A.,

lvrea(Turin), Italy [22] Filed: May 24, 1974 [2l] Appl No: 473,115

[30] Foreign Application Priority Data June l2, l973 Italy 25089/73 [52] US. Cl. i. 354/320; 355/]0; 355/27 [51] Int. Cl. ..G03D 3/08; G03B 27/32; 6038 27/52 [58] Field of Search 355/10, 27-29, 355/100; 354/3l6, 320, 32l, 319; 34/l48, l5l, 159, 157

[56] References Cited UNITED STATES PATENTS 2,478350 8/]949 Trump 354/319 X 3,689,147 9/1972 Suzuki 355/10 Primary ExaminerRichard A. Wintercorn Attorney. Agent, or Firml. J. Schaefer 57 ABSTRACT An improved copy sheet drying and delivering device for an electrostatic copy machine of the liquid developing type is provided in which the drying station following the liquid developing station comprises a pair of squeezing rollers and at least a pair of drying rollers constituted by a roller covered with natural or synthetic leather known on the market as chamois leather" or buck skin" and a pressing counter rollers; and in which the longitudinal axes of said pairs of squeezing and drying rollers are disposed in the machine along an ascendent curved path the nip of the last pair of drying roller being disposed adjacent to the sheet output slit of the machine, this slit is disposed at such a height with respect to the copy accumulating plane of the machine as to cause the outcoming sheet to take up a curved direction the concavity of which is turned toward the machine and such as to upset it so that the image becomes turned downward toward the accumulating surface.

5 Claims, 1 Drawing Figure q as i COPY SHEET DRYING AND DELIVERING DEVICE FOR REPROGRAPIIIC MACHINE BACKGROUND OF THE INVENTION l. Field of the Invention:

The present invention concerns a copy sheet drying and delivery device for a reprographic machine, in particular for an electrostatic copy machine of the liquid developing type, wherein the copy sheet is moved through a liquid developer bath and finally it is dried and delivered onto the outlet of said machine.

More particularly, the invention concerns a device which dries by means of rollers and the allocation thereof on the output path of the finished copies.

2. Description of the Prior Art:

Devices are known wherein the drying and the fixing operation of the copy sheet is executed by heating the surface bearing the image, by irradiation by lamps or ventilation by heated air, or by the combined action of both.

Said devices. however, in addition to dissipating a remarkable amount of electric power, also require a certain period of time from the time the machine is switched on to the time that it reaches the required rated temperature, so that consequently the first copies are normally not completely dried.

In addition in many reprographic machines, the delivery of the copy sheet occurs by laying the copy sheet on the output stacker with the image surface turned upward. Therefore, when a plurality of consecutive copies are obtained, the stacking order of the copy sheets in said stacker is such that the last copy delivered is located in the first stack position from the top toward the bottom, and its face bearing the image is turned upward. This requires a rearrangement of said copy sheets by the operator when the copying operation has come to an end, or the use of devices adapted to turn each sheet upside down when it is delivered.

Therefore an object of the invention is to provide an improved copy sheet drying and delivering device which obviates the above mentioned disadvantages.

Other objects of the invention will be best appreciated by the following description.

OBJECTS AND SUMMARY OF THE INVENTION According to the invention there is provided a copy sheet drying and delivering device in which the drying station comprises a pair of squeezing rollers and at least one pair of drying rollers comprising a roller covered with natural or synthetic leather and a pressing counterroller; and in which the longitudinal axes of said pairs of squeezing and drying rollers are disposed along an ascending curved path, the last pair of the drying rollers being located adjacent to the sheet output slit of the machine; this slit being disposed at a height, with respect to the copy accumulating surface; which is greater than the half length of the maximum format of said copy sheet. and less than the minimum format length of said copy sheet, so as to cause the outcoming sheet to take up a curved direction, the concavity of which is turned toward the machine and is such as to upset it so that the image becomes turned downwards toward the accumulating surface.

BRIEF DESCRIPTION OF THE DRAWING:

FIG. I is a lateral section of the device according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Represented in the drawing of FIG. 1 according to the preferred embodiment of the invention, are the developing station I and the drying station 2, belonging to a liquid toner developing reprographic machine.

The copy sheet transfer system through said stations consists of pairs of rollers: 4, 5; 6, 7', 8, 9; 10, II; fulcrummed on suitable machine pivots. The rollers 4, 6, 8, IO drive the corresponding counterrollers 5, 7, 9, 11, the former being set into motion by a motor through known systems not depicted in the FIGURE.

The rollers 6, 7, 8, 10 are of hard rubber and the rollers 9, II have their outer surface covered by layers 12 of natural or synthetic liquid absorbent material, generally known on the market as "chamois leather or buck-skin", assembled on a hard rubber substrate. The disposition of the axes of the pairs of rollers 6, 7; 8, 9', I0, I]; is such as to define for the copy sheets, which are moved between the rollers of each pair, a curved path which is concave downward and is ascending from the developing station I to a slit I3, provided in the machine frame, which represents the outlet of the copy sheet and is placed over a receptacle I4 adapted to receive and to accumulate the copy sheets coming out from the machine.

The slit height, with respect to the plane of the receptacle I4 is greater than the half of the maximum format length of the copy sheet and less than the minimum format length of said sheet.

During the copying operations, the copy sheet 18, driven by the pair of roller 4, 5 with the image side facing up, is moved through the toner developing bath I5, contained in the reservoir 16, and then it is seized and advanced by the squeezing rollers 6, 7 which remove the super abondant developing liquid. The sheet 18 is successively seized and advanced by the pairs of rollers 8, 9; and 10, 11 where the drying operation is carried out by the rollers 8 and I0 which are pressed against the corresponding rollers 9 and 11 provided with the chamois leather covering 12 which causes the absorption of the residual liquid by the porosity of the layer I2. In particular, the toner developer particles transferred by the liquid vehicle are absorbed by the porosity of the chamois leather layer 12 and are entraped therein.

The leather has a sufficient impregnating power so as to guarantee good sheet drying and cleanness for the most part of the machine operative life.

The leading edge I9 of the sheet 18 is then applied onto the output slit l3.

Owing to the curved path caused by the position of the longitudinal axes of the pairs of rollers, 6, 7; 8, 9; 10, II, the copy sheet 18 emerging from the slit shows a curvature, the concavity whereof is turned toward the machine (see the FIGURE). which aids its leading edge 19 to be laid onto the stacker I4, with the developed image side facing down.

This functionality is aided by the copy sheet weight and flexibility and, specially, by the slit height with respect to the plane of the stacker 14 compared to the length of the copy sheet. It is in fact required that the copy is not released by the outlet pair of rollers 10, ll before its leading edge is contacting the lying plane of the stacker.

It is intended that many changes, improvements and additions may be made to the device described without departing from the spirit and the scope of the present invention as claimed here below.

What we claim is:

I. In a reprographic machine of the liquid developing type having a liquid developing station and a copy sheet accumulating plane for receiving copy sheets discharged from the machine, a copy sheet drying and delivering device comprising:

a pair of squeezing rollers receptive of a copy sheet from the developing station for squeezing same; means receptive of the copy sheet for drying same comprising a plurality of pairs of drying rollers, at

the longitudinal axes of said pairs of squeezing and drying rollers in an ascending convex arcuate path from said developing station to said output slit to define a corresponding ascending arcuate guide path for the copy sheet carried to the output slit by said squeezing and drying rollers.

2. A device according to claim 1 wherein said output slit is located at a height with respect to the copy sheet accumulating plane which is not greater than the minimum format length of the copy sheet and not less than one half of the maximum format length of the copy sheet.

3. A device according to claim 2, wherein the nip of least one drying roller of each pair having the outer 5 last pair of drying rollers in said Paul is ocmed jacent to the output slit of the machine.

4. A device according to claim 1 wherein said absorbent material comprises natural leather.

5. A device according to claim I wherein said absorbent material comprises synthetic leather.

* l l l =l 

1. In a reprographic machine of the liquid developing type having a liquid developing station and a copy sheet accumulating plane for receiving copy sheets discharged from the machine, a copy sheet drying and delivering device comprising: a pair of squeezing rollers receptive of a copy sheet from the developing station for squeezing same; means receptive of the copy sheet for drying same comprising a plurality of pairs of drying rollers, at least one drying roller of each pair having the outer surface thereof covered by a layer of liquid absorbent material; and means for guiding the copy sheet from the developing station to turn it upside down upon discharge onto the copy sheet accumulating plane comprising an output slit from the machine and means mounting the longitudinal axes of said pairs of squeezing and drying rollers in an ascending convex arcuate path from said developing station to said output slit to define a corresponding ascending arcuate guide path for the copy sheet carried to the output slit by said squeezing and drying rollers.
 2. A device according to claim 1 wherein said output slit is located at a height with respect to the copy sheet accumulating plane which is not greater than the minimum format length of the copy sheet and not less than one half of the maximum format length of the copy sheet.
 3. A device according to claim 2, wherein the nip of the last pair of drying rollers in said path is located adjacent to the output slit of the machine.
 4. A device according to claim 1 wherein said absorbent material comprises natural leather.
 5. A device according to claim 1 wherein said absorbent material comprises synthetic leather. 